We cover every section of the GMAT with in-depth lessons, 5000+ practice questions and realistic practice tests.

## Up to 100+ points GMAT score improvement guarantee

### The best guarantee you’ll find

Our Premium and Ultimate plans guarantee up to 100+ points score increase or your money back.

## Master each section of the test

### Comprehensive GMAT prep

We cover every section of the GMAT with in-depth lessons, 5000+ practice questions and realistic practice tests.

## Schedule-free studying

### Learn on the go

Study whenever and wherever you want with our iOS and Android mobile apps.

# Plugging In: Using Good Numbers

Eleven years ago Tina was half as old as Ike will be in four years. If Ike is $$m$$ years old now, how old is Tina now in terms of $$m$$?
Correct. [[snippet]] Checking this answer gives >$$\frac{m}{2} + 13 = \frac{10}{2}+13 = 5 + 13 = 18$$ This matches your **goal value** of 18, and none of the other answer choices do. So that means this is the correct answer.
Incorrect. [[snippet]] If you check this answer choice, you get >$$4m - 11 = 4(10)-11 = 40-11 = 29$$ This doesn't match your **goal value** of 18, so eliminate this answer.
Incorrect. [[snippet]] You should not do any math here. It should be clear that this doesn't match your **goal value** of 18, so eliminate this answer.
Incorrect. [[snippet]] If you check this answer choice, you get >$$4m+11 = 4(10)+11 = 40+11 = 51$$ as the numerator. Dividing this by 2 will not give an integer, so this doesn't match your **goal value** of 18. Eliminate this answer.
Incorrect. [[snippet]] If you check this answer choice, you get >$$2m-7 = 2(10)-7 = 20-7 = 13$$ This doesn't match your **goal value** of 18, so eliminate this answer.
$$4m - 11$$
$$\frac{m}{2} + 13$$
$$\frac{1}{2m - 22}$$
$$\frac{4m +11}{2}$$
$$2m-7$$